Importance of Biochemistry

What do you know about Lipids sources types, foods and uses ?

lipids definition

Lipids definition, sources, types, foods uses and examples examples of lipids food

Lipids definition sources and uses and properties are listed in this article.Lipids are triglycerides of fatty acids. The word lipid is derived from Greek word lipos meaning fat. Sources of lipids in food

 lipids definition sources and uses
Fatty acids building blocks of lipids

Lipids are macromolecules made up of fatty acids.

Oil and fats

Lipids include oils and fats. Oils and fats are esters of long chain carboxylic (fatty)  acids with glycerol. Sources of lipids in food


Lipids definition sources and uses

These esters are made up of three fatty acids,  therefore, they are called triglycerides.

Oils at room temperature Sources of lipids in food

Oils exist in liquid form at room temperature.  They are triglycerides of unsaturated fatty acids. Sources of lipids in food

Fats at room temperature Sources of lipids in food

Lipids definition sources and uses
Saturated And unsaturated fatty acids

At room temperature the fats exist in solid form . They are triglycerides of saturated fatty acids. Sources of lipids in food

Fatty acids are building blocks of lipids.


They are long chain saturated or unsaturated carboxylic acids.

C15H31COOH palmitic acids

C17H35COOH stearic acid

Formation of esters by fatty acids

Esters (oils or fats) are formed  with glycerol from these acids  in the presence of mineral acids.

Sources of lipids

Fats and oils are high energy foods. They are source of vitamins A, D and E.

Uses Sources of lipids in food

They are used to build brain cells, nerve cells and cell membrane.

Properties Sources of lipids in food

In water they are insoluble but soluble in organic solvents. The fats stored in the body insulate it as they are poor conductor of heat and electricity.

Synthesis of fats and oils naturally

Fats and oils are synthesized naturally by animals, plants and marine organism.

1. Animal fats are found in adipose tissue cells. We get milk from animals from which we get butter and ghee easily . Butter and ghee are used by us for cooking and frying of food, for preparing bakery products and sweets. Sources of lipids in food

2. Animal fats are used in soap industry

3. Plants synthesize oils and store them in seeds,  such as sunflower oil,  coconut oil,  groundnut oil and corn oil. These oils are used as vegetable oils or ghee for cooking and other purpose. Sources of lipids in food

Marine animals like salmon and whales are also source of oils.  These oils are used as medicines e. g cod liver oil.

Types of lipids

Selection of foods that provide a variety of healthy fats.

The lipids are a diverse group of organic compounds consisting primarily of carbon, hydrogen and oxygen, and may sometimes contain sulfur , nitrogen or phosphorus .

There are three types of lipids in the different foods we eat: fats, phospholipids, and cholesterol . Let’s see in detail how they are classified, their characteristics and which foods contain them in greater proportion: Sources of lipids in food

Fats Sources of lipids in food

Saturated fats

They are considered as ‘the bad fats’, since when they are consumed in excess they can cause cholesterol problems and circulation disorders. It must be taken into account that high consumption of this type of fat, together with cholesterol from food, can cause serious heart problems, due to hardening of the arteries (atherosclerosis). Sources of lipids in food

Most saturated fat comes from animal foods like red meat and butter. Palm and coconut oils are also rich in these fats.

Unsaturated fats

Most unsaturated fats are oils, since at room temperature they are in a liquid state. They are beneficial fats for health because they regulate the level of cholesterol and prevent cardiovascular diseases . They may be: Sources of lipids in food

  • Monounsaturated fats: present in olive oil , rapeseed oil, nuts ( pistachios , almonds, hazelnuts, macadamia nuts or cashews), peanuts, avocados and their oils.
  • Polyunsaturated fats: found in sunflower oil, fish oil, soybean oil, corn, saffron , and also in oily fish such as salmon , tuna , sardines … In turn, polyunsaturated fats are subdivided into different types , highlighting two classes for their properties:
  • The omega 3 fats are present in many fish like blue fish (salmon, mackerel, tuna, sardines, trout and anchovies, and also in various dry and oil fruits like nuts, seeds, canola seeds Soy and its oils The best known omega 3 is linolenic acid. Sources of lipids in food
  • The omega 6 fats we can find in sunflower seeds, wheat germ, sesame, walnuts, soybean, corn and their oils. The best known is linoleic acid.The linoleic acid and linolenic acid can not be synthesized in the body and therefore must be obtained through the diet (EFAs).
  • Trans fats : These fats are produced through a chemical process called hydrogenation, which consists of adding hydrogen to some vegetable oils. This procedure is used in order to enhance the flavor and improve the texture of food products, prolonging their useful life at a low cost. However, hydrogenation causes a part of the polyunsaturated fats to be transformed into saturated fats which, as we have seen, it is not convenient to abuse. Therefore, it is advisable to check the labels to check if it contains trans fat, and limit its consumption. Sources of lipids in food
Phospholipids Sources of lipids in food

The contribution of fatty acids is of less importance than in the case of triglycerides . These intervene in the lipid transport functions and also have a structural role constituting the cell membrane. Phospholipids are part of the group of lipids derived from glycerol, their structure is similar to that of triglycerides, and they have better absorption and use of the latter.

Its daily contribution ranges between 2 and 8 grams. To take advantage of its virtues, you can choose foods such as walnuts or almonds, and egg yolk, which help regulate cholesterol, or a soy supplement known as lecithin, with satiating power, and others such as meat, organ meats, fish or seafood and cereals.

Cholesterol Sources of lipids in food

Cholesterol performs different functions within the body, although it is not considered an essential nutrient. Its functions include: Sources of lipids in food

  • Structural: it is basic in the formation of the cell membrane.
  • Precursor in the synthesis of sex hormones such as testosterone and cortisol. Sources of lipids in food
  • Precursor in the synthesis of bile salts: these emulsify fatty acids to make them more soluble in water, facilitating their absorption.

We can find them in the following foods: cream, egg yolk, lard, bacon, butter, milk, coconut oil, lean meat, nuts, avocado, olive and seed oils, etc. Blue fish, such as salmon, trout, sardines, tuna.

  • Eggs.
  • Meats.

High cholesterol foods

  • Pig liver.
  • Beef brains.
  • Veal.
  • Yolk.

Main types of lipids found in living organisms

1. Phospholipids Sources of lipids in food

They consist of two fatty acid chains, a phosphate group and a glycerol group. They contain molecules that attract and repel water, playing a key role in the constitution of cell membranes.

There are many types of phospholipids in the body, especially in the brain. In the body there are several forms that participate in the digestion of fat in the small intestine. Sources of lipids in food

The body is capable of producing all the phospholipids it needs.

2. Glycolipids 

Glycolipids are fat molecules that contain a sugar unit, such as glucose or galactose. Short sugar chains form glycolipids which can be found on the exoplasmic surface of a cell membrane. They play an important role in the development of the body’s immune system. Sources of lipids in food

3. Cholesterol 

Cholesterol is found in the cells and the bloodstream of humans. Because it is not soluble in the blood it must be carried into the cells with the help of lipoproteins.

Although too much cholesterol can be bad for the body, cholesterol is an important molecule. Sources of lipids in food

It is necessary to form cell membranes, and it is the precursor to other steroids, such as testosterone and estradiol.

4. Triglycerides 

Triglyceride molecules are made up of three fatty acid molecules and one glycerol molecule. Fat can be unsaturated or saturated.

A triglyceride will be classified as fat if it solidifies at a temperature of 20ºC, otherwise it is classified as oils.

Triglycerides are crucial in the body for energy storage. They are obtained from food sources of fat, such as cooking oils, butter, and animal fat. Sources of lipids in food

They play an important role in how the body uses vitamins. When not all the calories you consume are burned, they are converted into triglycerides and stored for future use.

If you consume more calories than you burn or eat too much fat-rich food, your triglyceride level could become too high and pose a health risk. Sources of lipids in food

5. Steroids

Some common types of steroids are cholesterol, testosterone, vitamin D2, and estrogen.

Steroids are a type of lipid that includes hormones and cholesterol. Cholesterol is produced by the body and consumed through food, and it plays a role in the production of hormones. The hormones include the sex hormones estrogen and testosterone and other hormones such as adrenaline, cortisol, and progesterone. Sources of lipids in food

6. Lipoproteins

A lipoprotein is a combination of proteins and lipids found on the membrane of a cell. Sources of lipids in food

Lipoprotein helps fat move around the body in the bloodstream and exists in the form of low-density lipoprotein (HDL) and high-density lipoprotein (LDL).

7. Wax

Waxes are very common lipids and can be found in animal feathers, human ears, and even plant leaves. Sources of lipids in food

Its main function is that of protection.

Sources of lipids in food

A scientific study has analyzed the lipid profile that reveals that a quarter of ingested fats come from olive oil (24%), although this contribution is higher among the adult population than in children, which included a total of 2,009 individuals between 9 and 75 years old with an average lipid intake of between 78.1 and 26.1 grams per day. Sources of lipids in food

In these cases, the main source of this macronutrient is the group composed of oils and fats (32.19%), followed by that of meats and derivatives (22.52%) and by that of milk and dairy products
(13 , 48%).

By food, 24 percent of the dietary sources of lipids are olive oil (24.4%), followed by meat (12.7%), sausages and meat products (9.6%), pastries and pastries (7.3%), cheeses (5.3%), milk (4.6%),
precooked (4.4%), other oils (4.4%), fish and shellfish (4.2%) and eggs (3.7%). Sources of lipids in food

However, the analysis by food and beverages subgroups shows differences according to the age group of the respondents . Although in all cases the main source of lipids is olive oil, among those under 9 to 12 years old (18%) it is lower than among those over 18 to 65 years old (24%). In addition, among the smallest the second food source is sausage and chocolate is among the 10 foods that provide the most lipids. Sources of lipids in food

In addition, if only the intake of monounsaturated fatty acids is taken into account , which according to data from the World Health Organization (WHO) should represent between 16 and 19
percent of all daily calories, it is observed that the intake is slightly higher in older adults and lower in children and adolescents. Sources of lipids in food

Where are they found?

We can classify foods according to the relative abundance in each of the types of fats: Sources of lipids in food

Foods rich in saturated fatty acids : lard, bacon, butter, cream, egg yolk, lean meat, milk, coconut oil.

Foods rich in monounsaturated fatty acids : Oleic (Omega 9): Oils (olive, seed), nuts (peanuts, almonds), avocado.

Conditionally essential polyunsaturated fatty acids :

EPA and DHA (Omega 3): fish and oil of pascado, algae, foods such as dairy products enriched in Omega 3

Arachidonic acid (Omega 6): animal fat

Essential polyunsaturated fatty acids:

Alpha Linolenic (Omega 3): in vegetable oils.
Linoleic (Omega 6): corn, sunflower, soy, grape seed oils

Foods rich in phospholipids : Meat and eggs.

Foods rich in cholesterol : beef brains, egg yolk, pork kidney, pork liver, beef.

The functions of lipids are very varied. We can distinguish the following: Sources of lipids in food

Energetic: triglycerides provide 9 kcal / g, more than double the energy produced by carbohydrates. In addition, they can accumulate and be used as reserve material in fat cells.

Structural: phospholipids and cholesterol are part of biological membranes.

Transport: dietary fat is necessary for the transport of fat-soluble vitamins A, D, E and K, as well as for their intestinal absorption.

Regulatory: cholesterol is a precursor of compounds of great biological importance, such as sexual or adrenal hormones and vitamin D that intervenes in the regulation of calcium metabolism. Sources of lipids in food

Examples of lipids food

Butter: Like aged cheeses, cream, these dairy products have a high fat content, which allows them to spread and give a characteristic flavor. Sources of lipids in food

Red meat: Veal and pork, meaning high-fat meats such as chops, sausages and bacon.

Seafood: Despite being succulent and high in iodine, they contain a significant lipid load that directly affects the body’s cholesterol.

Vegetable oils: Used as a salad dressing or as part of sauces and in cooking, they contain fatty acids that are often essential for life. Sources of lipids in food

Nuts and seeds: Like walnuts, peanuts, chia, sesame, almonds and chestnuts. In fact, they are often used in the production of oils for cooking or seasoning.

Eggs: Egg yolk (yellow part) contains an important lipid contribution.

Fat milk: While it is an important source of protein and carbohydrates, it is also an abundant source of fat, as this food is naturally intended to nourish developing people.

Fish: They are rich in fatty oils that are extremely beneficial to the body (Omega 3) and can even be consumed as a food supplement.

Soybeans or Soybeans: Legume used to obtain tofu oils and multiple applications as a food substitute.

Fried foods: This is due to its preparation, immersed in polyunsaturated oils. Flour, meat and seafood.

General needs and recommendations

The total fat should mean between 30-35% of total dietary energy . With regard to cholesterol , it is recommended not to exceed 300 mg per person per day. Current Spanish society exceeds these recommendations. Sources of lipids in food


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